Crack-growth inhibition by designing dendritic pattern for soft adhesives

Soft adhesive layers show promise in various engineering applications, including biomedicine, automotive, semiconductor, and aerospace industries. However, cavities trapped at the interface due to poor contact will significantly inhibit their adhesion capacity, leading to rapid crack-growth failure. Significant efforts in these applications within a confined contact area are focused on mitigating the effects and enhancing the debonding work of the interface without changing the materials, such as using bioinspired micropillars. However, soft adhesives with isolated contact elements face limitations due to manufacturing complexity and the collision of micropillars under large deformation. This study proposes a simple and effective method to reduce the hydrostatic pressure around the crack tips by designing a dendritic pattern within the confined area. This approach inhibited interface crack growth well and improved adhesive performance. As a result, the crack failure was delayed, with the stretch ratio enhanced by more than 36 %, while the debonding work increased by 85 % compared with the circular adhesive layer. This study demonstrates that adhesion capacity can be significantly improved while reducing material usage by designing dendritic patterns.